Telephone-exchange system.



M. S. GONNER.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED FEB.23,1906. I v

Patented 00$. 20, 1908.

fiZz/z'tnesaes: %mm4zd 7www UNITED STATES PATENT OFFICE.

-MERRITT S. (BONNER, OF ROCHESTER, NEW YORK, ASSIGNOR TO STROMBERG-OARLSON TELE- PH ONE MANUFACTURING COMPANY OF ROCHESTER, NEW YORK, A CORPORATION 01* 'usw roan TELEPHONE-EXCHANGE SYSTEM.

Patented Oct.- 20, 1908.

Application filed February 23, 1906; Serial No. 302,372.

T all whom it may concern:

Be it known that I, Mnunrr'r S. CONNER,

citizen of the lh ited States residing at Rochester, in the county of Monroe and State of New York, have invented a certain new and useful Improvement 111 Telephoneing drawings, forming a part ofthis specification.

My invention relates to tclephone'ex change systems and has for its object the provision of improved trunlcmeans for connecting subscri ersconnected with a s11b central exchange with subscribers connected witha main exchangc,;the main feature of the invention being the improved supervi- \s'ory mechanism and arrangement thereof.

In my improved tor at the sub-excl ngebascontrol of the application of ringing current to the called line, the operations'for setting the ringing mechanism in condition to be connected being controlled primarily by the trunk opcrator, and the mam invention resides in novel adjustment and arrangement of controlling and, supervisory relays.

My invention will be'better understood when described withreference to the accompanying drawing which diagrammatically shows the arrangement in accordance with my inventionJ The ,Sllb-StiLtl On A connects through the line limbs a and b withithe sub-exchange and is provided with the usual telephonic apparatus comprisingthe-transmitter, 1, receiver Qfand switch hook 3 normally connected in an open branch across the line limb, and a signal bell 4connected in bridge of the line, limbs with a condenser-5. The indicating relayfi at the exchange is normally connected through the armatures, 7

and 8, with the line limbs and with the common: source S and controls the circuit through the indicating lamp 9. The cut of! relay 10 controls the armatures 7 and 8 and connects between the positive-side of bat- .te and the thimbles 11 for-the multiple jac s 12. The cord circuit at the sub-centralexchange comprises the plugs 13 and 14 connectedthrough tip and sleeve "strands 15 and 1G, condensers l7 and 18 being interposed to divide the cord circuit into-two conduetivcly disconnected halves or parts. The cord cir-z rrangement the opera compoun supervisory relay 21 connects be tween the'slceve strand 16 on the answering side of the cord circuit and with the. negative side of. the battery S. The winding 22 of the supervisory relay connects between the tip strands 15 of the answering side and with the positive terminal of the battery S, this supervisory relay controlling the answering supervisory lamp 23. The winding 24 for the calling supervisory relay 25 connects between the negative side of the battery and the sleeve strand lfi of the calling side of the cord circuit, while the winding 26 connectsbetween positive side of the battery and the tip sirundi 15 at the calling side of the cord strand, this relay 33 controlling the circuit'for the calling supervisory lamp 27.

A trunk clrcuit at the main exchange M termmatesat one end in the springjack 2S and at the other end in the calling plug 29, the cord circuit "being divided into two conductively separated parts by means of rcpeating'coils 30 and 31, the windings 3:5 and 33 being included in the springjack side and separated by the condcuscr 3-4. while the windings 35 and 36 are included in the calling side and conductively separated by the condenser 37. The winding 2-38 of the calling tween the calling sleeve strand 4-0 and the negative side of the main exchange batter E and controls a plurality of contacts for change is a relay 45, theci'rcuit for thisrelay beingcontrolled at the trunk exchange by the relay 46 to be connected in circuit when .said relay 4-6 is inert, and anotlur.rcla 47 [is adapted to be substituted for the relay sideofsupervisory relay 39 connects l cbridge of the condenser 34 at thctrunkex' I when the relay'46 becomes active, all of which will be more fully described when r the operationof the system is described'and the circuits traced.

"The selective ringing mechanism for the trunk exchan 'e' is like that shown in the application Arthur R. Kahl, Serial No.

298,741 filed January 31, 1906, and this relay apparatus comprises any number of selective 'keys 48 and a suitable number of sources 49 for providing. selective signaling current. Interrupting mechanism 50 is also adapted to be included in the ringing cir- I cuit-upon' actuation of the key, each inter- 'rupter, as in the referred to application, be ng provided with a segment 51 connected 1 with ground (land a segment 52 connected Interrupters for the various keys are mounted on the same shaft '20 with: the generator.

with a'common interrupting means 53 provided with the grounded segment 54 and v the segment 55 connected with the armature 56 of a locking relay 57 which is also mea plication St 'chanically associated with the keys to lock 25 any'k y to maintain application of ringing current. As described in the aforesaid the segments 52 are slightly orter-than' the segment 54, the exact op- One connects with the eration of whichwill appear later. terminal of the relay 57 negative side of battery "E, while the other turn this relay in COIlJllIlCtlOIl with super-' vlsory relay 39 controls the circuit through the disconnect signal lamp 59. A controll ng relay 60 is also associated with the cord circuit, one of its terminals connecting with 65 with the armature 66 of the rela' the negative side of battery E and the other terminal connecting with contact 61 of relay 57. The contacts 62 and 63 connect with the terminals of the ringing circuit and are normally disconnected from the cord strands, the ringing lead 64 being also further controlled by contacts of relay 58. The sleeve strand 65' of the cord circuit is normally closed by engagement of the contact 57 while the tip strand 68 of the cord circuit is normally open at the contacts 69 and 7 O of-the supervisory relay 39 but closed at the contacts 71 and 72 of the relay 60.

The line limbsa and b of the called line terminating in spring acks 73 extend to a plurality-of party substations P}, ,'P, etc, each provided with a transmitter 1, receiver 2, hook 3 connected in a normally open branch of the line limbsand a signal bell 4 normally connected in a branch with a condenser 5'.. The indicating relay 6 is normally connected through arinatures 7 and 8 with the line and controls the 1nd1- eating lamp 9. V The cut off relay 10 connects between the positive side of battery E and with the jack thimbles 74.

The operators of the exchanges may also connect through the limbs c and d of an ordering circuit terminating at the subexchange in the springs 75 and 76 of the order key 77 and at the trunk exchange connecting through the windings ofthe relay 78 and source of current 79, this relay controlling the signal lamp 80. The trunk operators telephonic apparatus T also coimects with this order line and at the sub-exchange the operators set 0 will connect w1th the order line upon actuation of the order key7 7 i The operation of the system will now be readily understood. Suppose that the subscriber at substation A desires communication with a subscriber at substation P. I

Upon removal of the receiver 2 from the hook circuit will be closed, in a well known manner through the indicatinglrelay 6 to cause closure of the circuit through indicating lamp 9, in answer to which the sub-exchange operator inserts plug 13 into one of the sp'ringqacks 12, whereupon circuit I through the cut off relay 10 is completed through the sleeve strand 16 and the winding 20 of the supervisory relay, the signal lamp 9 being extinguished. Upon removal of the receiver, circuit is also closed through winding 22 and the associated contacts are disengaged to open the circuit of the supervisory lamp 23. The operator actuates her key 19 in the proper direction to connect her telephone set in circuit and ascertains from the calling subscriber the connection desired. She thereupon actuates order key 77 to complete the order circuit through her telephone set Which Will cause actuation of relay 78 to close circuit through the order lamp 80,

and the trunk operator by means of her telephone sct ascertains from the sub-exchange operator the connection desired and at the same time notifies the sub-exchan e operator which trunk circuit is to be used for making the connection, which in this case will bethe trunk circuit M. The trunk operator: com nects the calling plug '29 of the cord circuit with one of the s ringjacks 73 and this causes the circuit t rough cut-off relay 10 to be completed through the sleeve strand 40 and winding 38 to negative side of battery E, whereupon the indicating signal 9 be-- comes inert and relay 39 energized to close the following circuit: negative side of battery E through conductor 81, supervisor lamp 42, contacts 82 and 83 of relay 41, con ductors 84 and 85, contacts 86 and 87 of relay 39 and through conductor 88 tdipositive side of battery. lay 39 circuit is also closed from negative side of battery E through lamp 59, contacts Upon actuation of re- 89 and 90 of relay 58, through conductor 85,

contacts 80 and 87 and through conductor the keys 48 connected with the source which 2 is to provide signal current for selecting the desired substation, the key here used being the one indicated by reference character. Upon setting of this key the circuit is immediatel closed from the-negative side of battery It throu h conductor ,91, through relay 57, through ey 48, through conductor 92,

through contacts 93 and 94 of relay 46, through conductor 125, through conductor 85, through contacts 86 and 87 ofrelay 39 and through conductor 88 to the positive side of battery E, the relay 57 becoming eners gized to mechanically lock the actuated key 48 in. its depressed position and to attractits "armature 56 into engagement with contact 61 and to withdraw" its armature 60 from engagement with contact 65. \Vhen the segment',54 of interrupter 53 comes into contact with conductor 95 circuit may be traced from ground G through conductor 95, armature-56 and contact 01, conductor 96, through relay (t0, through conductor 91 and through battery E to ground. 'Relay (30 thereu on becomes energized to move the contacts 9 and 98 into engagement With cont acts 62 and 63 respectively connected with the terminals of the ringing circuit tocon meet these terminals with the cord strands leading to the. calling plug 29, the tip strand ofithe calling side having become continuous at contacts 69 and 7 0 upon actuation of relay 39 and the other partof the tip strand havin become disconnected from the calling si e upon disengagement of contact 71 from contact 98. Theother side of the sleeve strand of the cord circuit also becomes dis 0 connected at contacts 06 and 65 of the relay 57 from the calling end of the sleeve strain and upon a plicatlon of ringing, current this current -wil flow onlystoward the calling cord.

At the same time that circuit becomes closed through relay (30 the segment 52 connected with the signaling source 49 becomes connected with the key 48 and as soon as relay 58 becomes energized, as will be described presently, ring ng current will flow from generator 49 through segment 52, conductor 99, through key 48, through conduc- .tor (34, through contacts100 and 101 of the relay 58 when energized, through conductor 102, through contacts 63 and 72 of relay 60 and throu h the tip strand 68, thence fine and substation P back through the sleeve strand '40 through con tacts 97 and 62 of relay 00 and back through conductor 103 to generator 49. As before stated, however, the segment 52 of the interrupter 50 is slightly shorter than segment 540i the interrupter 53 but these segments 1 connect at the same time respectively with a signaling source 49 and with ground G, and therefore relay 57 and relay 60 controlled thereby are actuated at the same time. Owing to this difference in length of the lsegmcnts, however, relay 57 remains coni nected in circuit an interval after the segment 52 disconnects from the signaling source, anddn place of this segment 52 the grounded segment 51 is connected with the key 48 and during a short interval equivalent to the difference in length of the seg ments the cord circuit and lines will be grounded and thus relieved of any static charges which may have accumulated upon application of the alternating signaling current, this being similar to the arrangen'ient in the,applicat1on of Kahl referred to. The actuation of relay 58, however, depends upon the connection of the sub-excl'iange cord circuit with the trunk circuit, and therefore the ringing circuit is ineffective. The tsubexchange operator, however, having been notified by the main exchange operator which trunk was to be used in the connection, connected her calling plug 14 with the springjack 28 and circuit was immediately closed as follows: from negative side of battery S through conductor 104, supervisory winding 24, conductor 105, through the operators key and sleeve strand, through the sleeve contact of plug 14, through springjack 28, through winding of the repeating coil 31, through conductor 106, through contacts 107 and 108, through relay, 45, through conductor 109, through repeating coil winding 32, through springjack 28,'tip contact of plug 14, tip strandjof the subexchange cord circuit, through conductor 110, through supervisory winding 26, and through conductor 111 to positive side of battery S. Circuit through the windin 24 is also closed through a shorteripath rom the sleeve contact of plug 14 to test thimble 43 and impedance winding 44 tp positive side of battery S. Energization of winding 24 causes attraction of the armature 112 and if winding 20 were'ener 'ized the correspond ing armature 113 would be actuated to se )arate the contacts 114 and 115 controlling ine circuit through the supervisory lamp 27 Relay 45, however, is of sufiicifently hi'ghte sistancc When'connected incircuit withthe winding 26, as just described, to 'revent sufficient current flow to energizet is winding and therefore the supervisory 1am circuit will remain closed. This relay 45, owever, itself becomes energized and closes circuit through the relay-58 as follows: negative side of battery E through conductor 116, through relay 58, through conductor 117, through contacts 118 and 119 of relay 45 and through conductor 120 "toqm siti e sidc of battery E. Upon energization (yr-any .58 signallamp '59 becomes extinguished upon disconnection of contacts 89 and 90 which also completed upon energization of this relay to connect together contacts 100 and 101 and the signaling pulsations Wlll flow "through-the line and signal bell at the substation P which is to be called and thus final application of signaling current to a called line is automatically controlled by apparatus connected-with the trunk circuit, the operation of which apparatus 18 directly controlled by the sub-exchange operator,

ringing being prevented until the proper connection has been made by the sub-exchange operator with the trunk line.

Upon receiving the signal the subscriber at the called substation removes, the receiver from the hook and the following circuit is closed through the controlling relay 46 during the interval that the circuit through relay 60 is not completed through the interrupter 58: from negative side of battery E through conductor 81, supervisory relay winding 38, sleeve strand and contact of plug 29, through springjack 73, through the called substation telephonic apparatus back through springjack 73 to tip strand of contact 68 through closed contacts 69 and 70 through contacts 71 and 72 of relay 60, when said relay is inert, through conductor 121, through relay 46 and through conductor 122 to positive side of battery, and upon actuation of relay 46 several circuits are effected. In the first place upon disengagement of contacts 93 and 94 circuit through relay 57 is opened with a consequent release of the key 48 and disconnection thereby of the signaling apparatus. U on deenergization of relay 57 the circuit t rough relay 60 is permanently broken, and the cord circuit is restored to be continuous for subsequent transmission for telephonic currents. Upon energization of relay 46 circuit is also closed through relay 41 as follows: from negative side of battery E through relay 41,'through conductor 123, through contacts 124 and 94 of relay 46, through conductor 125, through conductor 85, through contacts 86 and 87 of relay '39 and through conductor 88 to positive side of battery, the circuit through supervisory lamp 42 being thereby opened.

The contact 107 of relay 46 disconnects from contact 108 and connects with contact 128 and the relay 47 will be substituted for the relay 45, current then flowing from conductor 106 through contacts 107 and 128, through conductor 129, through relay 47, through conductor 109 and through the re maining circuit before traced at the subcentral exchange. As relay 47, however, is .46. This local circuit may be traced from negative battery through the relay winding,

of lower resistance than relay 45 sufficient current may now How through winding 26 from the trunk circuit.

at the sub-central exchange circuit is opened through winding 22 of the supervisory relay to cause illumination of supervisory lamp 23. At the main exchange the circuit is opened through relay 46 and the circuit through relay 41 is reopened and lamp 42 reilluminated which indicates to the trunk operator that subscriber at substation i" is through talking. Restoration of relay 4-6 causes disconnection of relay 47 and rein-- clusion in circuit of high resistance relay'453, and the current flow through the circuit i11- cluding relay 4: and winding 26 of the supervisory relay is again reduced, whereby supervisory lamp 27 becomes illuminated. The sub-exchange operator now receives signals which indicate that both subscribers are through talking, and thereupon disconnects her cord circuit from the line and from the trunk circuit. This disconnects the circuit through relay 45, and relay 5S controlled thereby becomes deenergized, whereupon (lisconnect lamp 59 becomes illuminated upon rengagement of contacts 89 and 90, this giving the signal to the trunk operator that the sub-exchange operator has disconnected Upon disengagement of the trunk circuit from the line the entire system is in its normal state and ready for another connection.

An additional contact 132 is provided for contact 89 of relay 58 to which the lamp 59 connects, and this additional contact connects with the normal contact 133 of the supervisory relay This provides a signal for the trunk operator upon connection with the trunk circuit when the'calling side thereof is disconnected. l po'n connection, for instance, of the cord circuit at the subcentral exchange with this trunk circuit, relay 45, and consequently relay 58, will be actuated and current will flow through the lamp 59 from negative battery through the lam through contacts 89 and 132, through closing a local circuit therethrough after initial actuation thereof through the relay through contacts 134 and 83, through conthe spring jar-k, and through coiuluctor 88 to a sponse' to this disconnect signal operator disconnect-s the trunk ductor 85, throiigh contacts 86 and 87 of the relay 39 when the plug 29 is connected with positive side of battery. Lamp 42 will, theretore,rema1n extinguished until the subcentral exchange operator disconnects her cord circuit from the line to cause illuniination of the disconnect lamp t), and in rcthe trunk from the called line, and supervisory relay 39 becoming deenergized; circuit through both the relay 41 and the lamp 42 will be broken.

I thus provide improved supervisory and signaling means fortrunk circuit systems with which intermittent selective signalin is associated. This supervisory and signa ing-fineans cause the final application of ring ing' current to the line, to be called to be delayeduntil the sub-central exchange operator has made the proper connections withthe trunk line, this supervision being entirely automatic in its operations. p i

' I donot wish to be limited to the precise form of apparatus and arrangement'thereof herein shown and dcscribed,-as changes may readily be made without departing from the spirit ofthe invention glv; it

What I claim as new anddesire tosecnre by Letters Patent is: f" v combination --w1th acalling substation connected with a sub-central exchange to a telephone line, of a substation to be called. connected with the main exchange through a telephone line,

eachange forconnectionwith the line leading to the substation to be called, a cord cincuit at the sub-exchange for connection with the calling line and sand trunk c rcult, a supervisoryrelay for the cordcircuit, a controlling relay associated with the trunk circontrolled by circuit connecting) cuit and ada tedtuponconnection of the cord circuitwith the trunk circuit to'be connected in circuit with the supervisoryrelay, the resistance of said controllin relay being sufficiently high to norma y prevent operation of the supervisory relay, signaling apparatus associated with the trunk circuit, a second relay for controlling the connection of said signaling ap aratus withthe trnnk circuit and with the ine leadin to the sub station to be called, said secon relay being the controlling relay .an actuated to connect the signaling apparatus with the trunk circuit upon connection of saidcontrollingrelay in circuit with the. supervisory relay, and means adapted upon actuation of apparatus at the called substation in response to the signaling current for causing reduction of the resistance in the the supervisory controlling relay where y sufficient our cat may flow to operate the su ervisory rel y to indicate such response 0 the called substation.

second relay a telephone exchange system," the a trunk circuit at the main. means voperable upon 2. In a telephonefexchange systennuthe combination with acalling'substation connected with a sub-central exchange to a tele-.

phone line, of a substation to be called con eated with the main exchange through a telephone line, a trunk circuit at the main exchangefor connection with the line lead ing to the substation to be called, a cord 'cir cuit at the sub-exchange for connection with the calling line and said trunk circuit, a

trolling relay associated with the trunk, cir cult and adapted upon connection of'the cord circuit wlth the trunk circuit to be con- I nected in circuit with the supervisory relay, the resistance of said controlling relay being sufiiciently'high to normally prevent operation of the supervisory relay, si nalin apparatus associated with the tpun for controlling the connection of said si aling ap' circuit an with the ine leading to the substation to be called, said second relay being controlled by the, controlling relay and actuated to connect the signaling apparatus with the trunk circuit upon connection of said controlling relay in circuit with the aratus with the trunk 15 supervisory relay for thercord circuit,'-"a @onr supervisory relay, means upon actuation of i apparatus 'at the called substation .in response to the signaling current for causing reduction of the resistance in the circuit connecting the supervisory controlling relay whereby sufficient current may flow to op-' erate the supervisory relay to indicate such response of the called substation, and fuidiher actuation of the substation apparatus for-causing the second relay to be controlled to disconnect the signaling apparatus from the trunk circuit and line. i

3. In a telephone exchange system, the

combination with a calling substation connectedwvith a sub-central exchange o a tele- "phone line, of a substation to be called con-v nected with the main (exchangethrough a telephone line, a trunk circuit at the main exchange for connection with the line leading to the substation tobe called, a cord cirthecalling line and said trunk circuit, a supervisory relay for k trolling relay associated with the trunk C11- cuit at the sub-exchange for connection with 1 the cord circuit, a concuit and adapted upon connection of the cord circuit with the trunk circuit to be con- .nected in circuit with the supervisory relay,

the resistance of said controlling relay being sufficiently high to normally prevent opera-1 tion of the supervisory relay, a lower resistance' circuit iassociated ivith the control ling relay, signaling apparatus associat d with the trunk circuit, a second relay controlling the paatus with the trunk circuit, said scmnd relay being controlled by the controlling relay, a main relay associated with the trunk connection of said signaling apcircuit and controlling the high resistance relay and the lower resistance circuit asso ciated therewith, said second relay being controlled by the controlling relay upon connection of said controlling relay in circuit through the supervisory relay to connect the signaling apparatus with the trunk circuit whereby the substation to be called is signaled, and means operable upon actuation of apparatus at the called substation-in response to the signaling current for causing actuation of the main relay to render the low resistance circuit effective whereby suhicient current may flow to cause operation of the supervisory relay to indicate such response of the called substation.

4. In a telephone exchange system, the combination with a calling substation connected with a sub-central exchange to a tele phone line, of a substation to be called connected with the main exchange through a telephone line, a trunk circuit at the main excliai'ige for connection with the line leading to the substation to be called, a cord circuit at the sub-cxchaiige for connection with the calling line and said trunk circuit, a supervisory relay for the cord circuit, a controlling relay associated with the ti'uiikcircuit and adapted upon connection of the cord circuit with the trunk circuit to be connected in circuit with the supervisory relay, theresistancc of said controlling relay being sutlicieiitly high to normally prevent operation of the supervisory relay, a' low resistance relay, a third relay controlled by said low and high resistance relays, signaling apparatus adapted for connection with the trunk circuit upon actuation of the third relay to send si 'naling current to the substation to be called, and a main relay, actuation of substation apparatus in response to the signal-' ing current causing actuation of the main relay to substitute the low resistance relay for the high resistance relay whereby the supervisory relay may operate to indicate the response of the called substation.

A 5. In a telephone exchange system, the

combination with acalling substation con-'.

llQCiICd with a sub-central exchangeto a telephone line, oi a substation to be called connected. with the main exchange through a telephone line. a trunk circuit at the main exchange for connection with the line leading to the substation to be called, a cord circuit at the sub-exchange for connection with the calling-line and said trunk circuit, a super visory relay for the cord circuit, a controlling relay associated with the trunk circuit and adapted upon connection of the cord circuit with the trunk circuit to be connected in circuit with the supervisory relay, the resistance of said controlling relay being sufliciently' high to normally prevent operation of the supervisory relay, signaling apparatus at the ina'iirexcl ange, relay mechanism for connecting the signaling apparatus with the trunk circuit, additional relay mechanrelay for the high resistance relay whereby the supervisory relay may operate to indicate the response of the called substation, said additional relay mechanism upon deenergization of the high resistance relay being thereafter controlled by the low resistance relay, actuation ofthe main relay also causing operation of the first relay mechani'sin to disconnect the signaling apparatus from the trunk circuit. i

6. In a telephone exchange system, the

combination with a cord circuit, of a trunk circuit, a supervisory relay associated with the cord circuit, a high resistance relay associated with the trunk circuit, connection of said cord circuit'with the trunk circuit causing the supervisory relay and the high re sistance relay to be connected in a circuit whereby the high resistance relay is actuated,

the resistance, however, being sufiicient to prevent operation of the supervisory relay,

signaling apparatus associated with the trunk circuit, a controlling relay for controlling the final connection of the signaling apparatus with the trunk circuit, said contrplling relay being normally controlled by the high resistance relay, a low resistance relay, and a main relay adapted upon actuation to substitute the low resistance relay for the high resistance relay whereby the supervisory relay may operate, the control of the controlling relay being transferred to the low resistance relay upon'such substitution.

In witness whereof, I hereunto subscribe my name this 20th day of Feby. A. D., 1906.

M. S. CONN ER.

\Vitnesses:

E. A. HAWKINS, C. E. HAGUE. 

